1. Field of the Invention
This invention relates to a stator for an impact crusher for separation of compound materials, with an outer face of the casing wall and an inner face of the casing wall, which is plated with a plurality of plates with ribs, wherein the plates are designed as wear parts and are attached replaceably.
2. Discussion of Related Art
Impact crushers are used in a variety of different technical fields, but herein only the use regarding the separation of compound materials is of interest. Such compound materials can be compounds of metal/metal, plastic/plastic, metal/plastic or mineral compounds with metals and/or plastics. Because the physical properties of the individual components of the compounds are different, such compound particles are separated in impact crushers and with each impulse different materials deform unequally elastically and unequally plastically and thereby separate. Typical compound materials, which are processed by the applicant are, for example, electronic waste and shredder waste of all kind, in particular from car recycling.
The use of impact crushers in this area is associated with enormous wear of the hammer tools as well as of the crusher walls. Accordingly the crusher walls, which are the inner casing wall of respective stators of such impact crushers, are plated with replaceable plates, which comprise ribs, on which particles of the compound materials to be delaminated impinge with high energy. As soon as the ribs are reduced to a certain minimum due to respective wear, the plates have to be replaced. Typically, such plates are made from steel plates and the ribs are formed by slotting machines or by milling. The back side of such plates are fitted to the actual casing wall of the stator.
From Great Britain Patent Reference GB-A-1397674 an impact crusher is known, the stator of which comprises a carrier plate on which a plurality of rib-shaped projections are welded, between which hammer tools are rotating pivotably supported on a rotor. The respective plate is attached to hydraulic-slide elements in order to adjust the plate according to the wear. After wearout of the projections, the entire adjustable base plate has to be replaced accordingly. This requires a relatively complex disassembly.
From PCT Patent Reference WO 00/53324 (BHS Sonthofen) another impact crusher is known, which represents the closest prior art. This stator of an impact mill serves for separation of compound materials and comprises an outer face of the casing wall as well as an inner face of the casing wall, which is plated with a plurality of plates with ribs, wherein the plates are designed as wear parts and are attached replaceably. This known solution intends to simply hook-in the plates tile-like at the upper edge of the stator casing wall. Accordingly, the plates have a continuous longitudinal rib with a hook-shaped cross section extending on the upper edge portion. This longitudinal rib engages in a ring groove formed on the stator wall. Along the periphery of the stator a plurality of such plates are hooked-in. The plates, which have a relatively high weight, are kept in position solely by gravity and are positioned abutting each other relatively tight. Normally, such plates are easy to replace but the mounting of these plates carries a potentially high risk. The peripheral speed in such impact crushers can be up to several hundreds km/h, which represents a high potential energy. If bigger parts get into the impact crusher, which accordingly are hard, because the shredder could not crush them, then these parts can be wedged in between the rotor and the stator. Although the hammer tools are typically supported pivotably, instantaneous acceleration forces occur, which can result in displacing of the plates or even in unhooking. After such an event a complete revision of the impact crusher is necessary.